Small commercial laundry or clothing washer machines, for loads of less than 50 pounds or less than 25 kilograms, typically require three chemicals to be dispensed into the washer during a sequence of three or more bath cycles. The chemical dispensers for most commercial laundry machines are provided, usually at little or no cost to the customer, by the chemical supply company that provides the supplies for each particular laundry machine. However, since most small commercial laundry machines use relatively small amounts of chemicals, the amount of revenues generated for the sale of such chemicals is also small, and therefore it is important that the chemical dispensers for such machines be inexpensive.
One factor that makes many prior art chemical dispensers expensive, as well as difficult to install, is the need to connect the chemical dispenser to the sequence controller of the laundry machine. The sequence controller, which is standard equipment on industrial and commercial washers, produces a sequence of output signals that cause water to fill the machine's bath, to agitate the batch contents, to drain the bath, and to repeat that process several times at various intervals.
Another factor that makes prior art chemical dispensers expensive is the operator interface. The operator interface must facilitate the execution of several standard functions, including calibrating each of the dispenser's pumps accurately and quickly, programming the dispenser to perform sequences of chemical dispensing steps in coordination with the washer machine's wash cycles, and activating the dispenser to run a particular programmed sequence of dispensing steps when running the washer machine. The hardware and software required to execute these functions should be minimized to reduce the expense of the chemical dispenser system.
It is a general object of the present invention to provide a low cost liquid chemical dispenser.
It is a related object of the invention to provide a method and apparatus that requires minimal memory space to store a liquid dispensing program.
It is another object of the invention to provide a method and apparatus that requires minimal computing power to execute a liquid dispensing program.
It is another object of the invention to provide an operator interface that is physically compact.
It is still another object of the invention to provide an operator interface that is easy to program.
It is a related object of the invention to provide an operator interface that utilizes chemical calibration units for convenient operator programming.
It is a related object of the invention to provide delay time units for convenient operator programming.
It is another object of the invention to eliminate the need to electrically connect a chemical dispenser to a laundry machine's sequence controller.